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        // 1.绝对值方法
        console.log(Math.abs(1));//1
        console.log(Math.abs(-1));//1
        console.log(Math.abs('-1'));//隐式转换 会把字符串-1 转换为数字型
        console.log(Math.abs('pink'));//NaN
        // 2.三个取整的方法
        // (1)Math.floor()地板   向下取整  往最小了取值
        console.log(Math.floor(1.1));//1
        console.log(Math.floor(1.9));//1
        // (2)Math.ceil ()天花板 向上取整  往最大了取值
        console.log(Math.ceil(1.1));//2
        console.log(Math.ceil(1.5));//2
        console.log(Math.ceil(1.9));//2
        // (3)Math.round()四舍五入 其他数字都是四舍五入，但是.5特殊  它往大了取
        console.log(Math.round(1.1));//1
        console.log(Math.round(1.5));//2
        console.log(Math.round(1.9));//2
        console.log(Math.round(-1.1));//-1
        console.log(Math.round(-1.5));//-1
    </script>
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